Dinitroaniline herbicides such as pendimethalin and trifluralin, and oxyacetamide herbicides such as fluthiamid are known in the art. Combination treatments using these types of herbicides are disclosed in U.S. Pat. Nos. 4,968,342 and 5,759,955; and in German Application No. 19720367. However, emulsifiable concentrate compositions comprising dinitroaniline and oxyacetamide herbicides are not known in the art.
U.S. Pat. No. 3,898,075 relates to stabilized liquid compositions containing m-biscarbamates and organic acids. U.S. Pat. No. 2,954,396 describes a method for stabilizing carbamate esters with certain hydrolysis inhibitors. However, neither U.S. Pat. No. 3,898,075 nor U.S. Pat. No. 2,954,396 describe any method for the stabilization of oxyacetamide herbicides.
It is therefore an object of the present invention to provide stable emulsifiable concentrate compositions of dinitroaniline herbicides and oxyacetamide herbicides.
Other objects and advantages of the present invention will be apparent to those skilled in the art from the description below and the appended claims.
The present invention relates to a herbicidal emulsifiable concentrate composition comprising, on a weight to weight basis, about 15% to 40% of a dinitroaniline herbicide, about 1% to 10% of an oxyacetamide herbicide, about 0.01% to 1% phosphoric acid, up to about 30% of an emulsifier or mixture of emulsifiers, up to about 1% of an antifoaming agent, and an organic solvent or mixture of organic solvents.
The herbicidal emulsifiable concentrate compositions of this invention comprise, on a weight to weight basis, about 15% to 40% of a dinitroaniline herbicide, about 1% to 10% of an oxyacetamide herbicide, about 0.01% to 1% phosphoric acid, up to about 30% of an emulsifier or mixture of emulsifiers, up to about 1% of an antifoaming agent, and an organic solvent or mixture of organic solvents.
Preferred herbicidal emulsifiable concentrate compositions of the present invention are those comprising, on a weight to weight basis, about 15% to 40% of a dinitroaniline herbicide, about 1% to 10% of an oxyacetamide herbicide, about 0.01% to 1% phosphoric acid, about 2% to 10% of an alkylarylsufonate, about 0.5% to 5% of a polyalkylene glycol ether, about 1% to 5% of an ethoxylated fatty alcohol, up to about 1% of an antifoaming agent, and an aromatic hydrocarbon solvent having a distillation range of about 135xc2x0 C. to 305xc2x0 C.
More preferred emulsifiable concentrate compositions of this invention are those comprising, on a weight to weight basis, about 25% to 35% pendimethalin, about 4% to 8% fluthiamid, about 0.05% to 0.2% phosphoric acid, about 2% to 6% of a dodecylbenzenesulfonate, about 1% to 3% of an alkyl capped ethylene oxide/propylene oxide block copolymer, about 1% to 5% of an ethoxylated C10-C16fatty alcohol having about 8 to 12 moles of ethylene oxide per mole, up to about 1% of an antifoaming agent, and an aromatic hydrocarbon solvent having a distillation range of about 135xc2x0 to 305xc2x0 C.
Phosphoric acid is an especially important element of the present compositions because it has been found that oxyacetamide herbicides are more stable in the phosphoric acid containing emulsifiable concentrate compositions of the present invention than in corresponding emulsifiable concentrate compositions which do not contain phosphoric acid. In a preferred embodiment of the present invention, the ratio of the oxyacetamide herbicide to the phosphoric acid, on a weight basis, is preferably about 30:1 to 100:1, and more preferably, is about 40:1 to 70:1.
Dinitroaniline herbicides suitable for use in the compositions of this invention have the structural formula I 
wherein
R is hydrogen, C2-C4alkyl or chloroethyl;
R1 is C2-C5alkyl, chloroethyl, 2-methallyl or cyclopropylmethyl;
R2 is hydrogen, methyl or amino; and
R3 is trifluoromethyl, C1-C3alkyl, SO2NH2 or SO2CH3.
Preferred dinitroaniline herbicides for use in this invention include pendimethalin and trifluralin with pendimethalin being more preferred.
Oxyacetamide herbicides suitable for use in the compositions of the present invention are those described in U.S. Pat. Nos. 4,408,055; 4,509,971; 4,540,430; 4,549,899; 4,585,471; 4,645,525; 4,756,741; 4,784,682; 4,788,291; 4,833,243; 4,968,342; 4,988,380; 5,090,991 and 5,234,896; EP Application Nos. 300344-A and 500934-A1; and WO 97/08160.
Preferred oxyacetamide herbicides for use in the compositions of this invention have the structural formula II 
wherein
R4 is hydrogen, F, Cl, Br, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy, C1-C4haloalkoxy, C1-C4alkylsulfonyl or C1-C4haloalkylsulfonyl;
R5 is hydrogen or C1-C6alkyl; and
R6 is phenyl optionally substituted with any combination
of from one to three F, Cl, Br, CN, NO2, C1-C4alkyl,
C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups.
More preferred oxyacetamide herbicides for use in the emulsifiable concentrate compositions of this invention are those wherein
R4 is C1-C4haloalkyl;
R5 is C1-C4alkyl; and
R6 is phenyl optionally substituted with any combination
of one or two F, Cl or C1-C4alkyl groups.
Most preferred oxyacetamide herbicides are those of formula II wherein
R4 is CF3, CHF2 or CFCl2;
R5 is isopropyl; and
R6 is selected from the group consisting of phenyl, 3-chlorophenyl, 4-chlorophenyl, 2-fluorophenyl, 4-fluorophenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl and 3,4-dimethylphenyl.
An oxyacetamide herbicide which is especially suitable for use in the compositions of this invention is 4xe2x80x2-fluoro-N-isopropyl-2-{[5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl]oxy}acetanilide (fluthiamid).
Emulsifiers suitable for use in the compositions of the present invention include, but are not limited to, alkylarylsulfonates including C8-C18alkylbenzenesulfonates such as calcium dodecylbenzenesulfonate; polyalkylene glycol ethers including alkyl capped ethylene oxide/propylene oxide block copolymers such as butyl capped ethylene oxide/propylene oxide block copolymers; and ethoxylated fatty alcohols including ethoxylated C10-C16fatty alcohols having about 8 to 12 moles of ethylene oxide per mole; and mixtures thereof. Preferred emulsifiers include the alkali metal or alkaline earth metal salts of dodecylbenzene sulfonic acid, such as calcium dodecylbenzenesulfonate including SOPROPHOR(copyright) 70 a 60% calcium dodecylbenzene sulfonate solution in isobutanol commercially available from Rhodia, Milan, Italy; butyl capped ethylene oxide/propylene oxide block copolymers including WITCONOL(copyright) NS 500K a butyl capped ethylene oxide/propylene oxide block copolymer commerically available from Witco SA, Saint-Pierre Les Elbeuf, France; and ethoxylated C10-C16fatty alcohols having about 8 to 12 moles of ethylene oxide per mole including RHODASURF(copyright) 870 a C13 ethoxylated fatty alcohol containing 10 moles of ethylene oxide per mole commercially available from Rhodia, Milan, Italy; and mixtures thereof.
Organic solvents suitable for use in the compositions of this invention include aromatic hydrocarbon solvents such as toluene, xylenes, polynuclear aromatic hydrocarbons such as naphthalenes and alkylnaphthalenes and mixtures thereof, many of which are available from the fractionation of crude oil and in general have distillation ranges in the temperature range of about 135xc2x0 C. to 305xc2x0 C., with those having a distillation range of from about 183xc2x0 C. to 290xc2x0 C. being most preferred. These solvents are commercially available under a variety of tradenames, e.g. SOLVESSO(copyright)200 and AROMATIC(copyright)200 both commercially available from Exxon, Fareham, Hants, United Kingdom.
Antifoaming agents suitable for use in the compositions of the present invention include conventional antifoaming agents, with silicone based antifoaming agents such as those sold under the SILCOLAPSE(copyright) tradename commercially available from Rhodia, Lyon, France being preferred. In a preferred embodiment of this invention, an antifoaming agent is used at a level sufficient to prevent undesirable foaming during the preparation of tank mixes using the emulsion concentrates of the present invention. Typically, less than 1% by weight of a defoamer is sufficient, with amounts of about 0.01 to about 0.1% by weight being preferred.
The herbicidal emulsifiable concentrate compositions of the present invention may be prepared by admixing all of the ingredients in the organic solvent. In a preferred embodiment of this invention, the compositions are prepared by:
(a) admixing an alkylarylsulfonate, an ethoxylated fatty alcohol, an antifoaming agent and an organic solvent to obtain a first homogeneous mixture;
(b) adding a molten dinitroaniline and a molten polyalkylene glycol ether to the first homogenous mixture of step (a) with stirring to obtain a second homogenous mixture;
(c) adding an oxyacetamide herbicide to the second homogenous mixture of step (b) with stirring to obtain a third homogenous mixture; and
(d) adding phosphoric acid to the third homogenous mixture of step (c) with stirring.
The emulsifiable concentrate compositions of this invention are diluted with water and applied as dilute, aqueous emulsions to the locus where weed control is desired. Typical dilution rates are in the range of about 1 L of concentrate per 400 L of water to 4 L of concentrate per 100 L of water. While the compositions of this invention are effective for controlling weeds when employed alone, they may also be used in conjunction with or in combination with other biological chemicals, including other herbicides.
In order to facilitate a further understanding of the invention, the following examples are presented primarily for the purpose of illustrating more specific details thereof. The scope of the invention should not be deemed limited by the examples, but encompasses the entire subject matter defined in the claims.